You are about 20 years out of date. Modern politicians get almost all of their funding from small donations, in other words, from passionate partisans who care about culture war issues.
Have you evidence?
Only 6-8% of us political funding in 2024 came from business-PAC contributions.
https://www.fec.gov/resources/campaign-finance-statistics/20...
Further splits here: https://www.fec.gov/resources/campaign-finance-statistics/20...
There are exceptions to this of course but most politicians answer to voters much much much more than big business.